REASONの紹介 / Introductory talk about REASON

Reasonとは
Reasonが提供するもの
なぜOCamlを選んだのか
Messenger.comの50%はReasonに以降済み
文法：let束縛，型の構文，バリアント，パターンマッチ
JavaScriptとの相互運用
コンパイル出力の例

Transcript

1. ɹɹɹɹɹɹɹɹɹ ͷ঺հ Meguro.es #15 2018.5.22 tipo159
2. Reasonͱ͸ • Facebook͕2016೥ʹެ։ͨ͠OCamlΛJavaScriptʹࣅͤͨݴޠ
   • Facebook͸OCamlΛJavaScriptʹίϯύΠϧ͢ΔBuckleScriptͷ։ൃΛ 2012೥͔Βߦͳ͍ͬͯͯɼReasonͷαϙʔτΛ2016೥ʹ௥Ճ
   • Reasonͩͱݕࡧ͠ʹ͍ͨ͘ΊɼReasonMLͱॻ͔ΕΔ͜ͱ΋͋Δ
   • 2018.5.6ʹϦϦʔε͞Εͨ3.1.0͕࠷৽
   • 3FBTPO
   3FBTPO3FBDUͱ΋.*5ϥΠηϯε 2
3. Reason͕ఏڙ͢Δ΋ͷ • ݫ֨Ͱڧ͍ܕγεςϜ
   • ܕਪ࿦
   
   ܕఆٛΛ͠ͳͯ͘΋ίϯύΠϥ͕ܕΛਪ࿦
   • ݈શੑ Soundness
   
   ίϯύΠϧͰ͖Ε͹ܕ͕ਖ਼͍͜͠ͱΛอূ
   • 5ZQF4DSJQUͷܕγεςϜ͸ɼ+BWB4DSJQUͱͷޓ׵ੑͷͨΊ݈શͰ͸ͳ͍
   • γϯϓϧͰ࣮༻త
   • جຊతʹ͸७ਮɾΠϛϡʔλϒϧɾؔ਺ܕ͕ͩɼ໌ࣔ͢Ε͹෭࡞༻ɾϛϡʔςʔ γϣϯɾΦϒδΣΫτΛ࢖༻͢Δ͜ͱ΋Մೳ
   • ੑೳͱαΠζ
   • ReasonͷϏϧυγεςϜbsb͸ΠϯΫϦϝϯλϧϏϧυΛ100msҎԼͰऴྃ͠ɼ ੜ੒͞ΕΔίʔυ΋খ͍͞ʢϞδϡϥʔԽ͞ΕͨϥϯλΠϜʹΑΓ࢖༻͠ͳ͍ίʔ υΛ࡟আ͢ΔͨΊʣ 3
4. Reason͕ఏڙ͢Δ΋ͷʢଓ͖ʣ • ΠϯΫϦϝϯλϧͳֶशͱίʔυͷม׵͕Մೳ
   • JavaScriptΛࠞࡏͤ͞Δ͜ͱ͕Մೳ
   • ΤίγεςϜͱπʔϧ
   • ೚ҙͷΤσΟλʔɼnpmύοέʔδɼόϯυϥ΍ςετϑϨʔϜϫʔΫͳͲ͕࢖ ༻Մೳ 4
5. ͳͥOCamlΛબΜͩͷ͔ • ωʔςΟϒίʔυΛੜ੒Մೳ
   • OCamlͷωʔςΟϒίʔυ͸ҰܻϛϦඵͰىಈ
   • কདྷతʹ͸ReasonΛωʔςΟϒίʔυͰಈ࡞͍ͤͨ͞
   • ෭࡞༻ɾϛϡʔςʔγϣϯͳͲΛ࢖༻Մೳ
   • طଘͷίʔυΛҠߦ͢ΔͨΊʹ͸ɼ෭࡞༻ͳͲΛαϙʔτ͠ͳ͍ݴޠͰશ໘తʹॻ͖௚͢ΑΓɼ ෭࡞༻ͳͲΛαϙʔτ͢ΔݴޠͰগͣͭ͠Ҡߦ͢Δํ͕ݱ࣮త
   • ࣮૷ͷख़੒౓
   • OCaml͸20೥Ҏ্։ൃ͕ߦΘΕɼຖ೥ྑ͘ͳ͍ͬͯΔ
   • ReactΛهड़͢ΔͨΊͷݴޠ
   • Reasonͷ։ൃऀ͸ReactJSͷ։ൃ΋͓ͯ͠ΓɼReactJSͷ࠷ॳͷϓϩτλΠϓ͸ελϯμʔυ .-Ͱهड़
   • 2017೥ʹReactJS͸͸ReasonͰ΋هड़ՄೳʢReasonReactʣʹͳͬͨ 5
6. Messenger.comͷ50%͸ReasonʹҠߦࡁΈ • 2017.9.8ͷϒϩάهࣄ
   https://reasonml.github.io/blog/2017/09/08/messenger-50-reason.html • Facebook MessengerͷWeb൛͕Messenger.comɼfacebook.comͷΠϯϘοΫεϏϡʔͱ νϟοτλϒͰίʔυΛڞ༗
   • ̍೥Ҏ্͔͚ͯ50%ͷҠߦΛ࣮ࢪ
   • ౷ܭ৘ใ
   • Reason෦෼ʢ਺ඦϑΝΠϧʣͷϑϧϏϧυ͕2ඵҎԼɼΠϯΫϦϝϯλϧϏϧυ͸ฏۉ 100msҎԼ • Ҏલ͸ຖ೔όάϨϙʔτ͕ૹΒΕ͖͕ͯͨɼ3FBTPOʹҠߦͨ͠෦෼ͷόά͸̍೥ؒͰ݅
   • ΄ͱΜͲͷ.FTTFOHFSίΞ։ൃνʔϜ͸ɼ৽نػೳΛ3FBTPOͰ։ൃ
   • 3FBTPO3FBDUΛಋೖͨ͠਺ेճͷϦϑΝΫλϦϯάʹΑΓɼϦϑΝΫλϦϯάͷεϐʔυ ͸਺೔͔ΒᏐे෼ʹ·Ͱ୹ॖ 6
7. จ๏ɿletଋറ • MFUଋറ
   w ม਺એݴ୅ೖͰ͸ͳ͘ɼMFUͰ஋Λ໊લʹଋറ
   • ϒϩοΫείʔϓ
   • ଋറ͸\^ͷείʔϓ಺Ͱ༗ޮ
   if (displayGreeting) { let message = “Enjoying the docs so far?”; print_endline(message) }; /* `message`͸͜͜Ͱ͸ΞΫηεෆՄೳ
   
   w ଋറ͸Πϛϡʔλϒϧ
   • Ұ౓஋ʹଋറͨ͠Βɼଞͷ஋Λࢀর͢Δ͜ͱ͸Ͱ͖ͳ͍
   • ಉ໊͡લͰ৽͍͠ଋറΛߦ͏ͱݹ͍ଋറ͸γϟυ΢͞ΕΔʢࢀরͰ͖ͳ͘ͳΔʣ
   let message = “hello”; print_endline(message); /* “hello”ΛϓϦϯτ */ let message = “bye”; print_endline(message); /* “bye”ΛϓϦϯτ */ 7
8. จ๏ɿܕͷߏจ • Ξϊςʔγϣϯʢ஫ऍʣ
   ܕਪ࿦Λߦ͏ͨΊɼܕͷهड़͸͠ͳͯ͘΋Α͍
   let score = 10; let score: int = 10 let add = (x: int, y: int) : int => x + y; • ΤΠϦΞεʢผ໊ʣ
   • ܕʹผͷ໊લΛ෇͚Δ͜ͱ͕Մೳ
   type scoreType = int; let x: scoreType = 10; w ܕਪ࿦ʹؔ͢Δิ଍৘ใ
   w VSCodeͷίʔυϖϯͳͲͷΤσΟλػೳͰɼશͯͷίʔυͷܕΛදࣔՄೳ 8
9. จ๏ɿόϦΞϯτ • Ϩίʔυ͸ෳ਺ͷσʔλΛ·ͱΊΔ͕ɼόϦΞϯτ͸ෳ਺ͷσʔ λͷͲΕ͔Λදݱ
   type myResponseVariant = | Yes | No | PrettyMuch; let areYouCrushingIt = Yes; 9
10. จ๏ɿύλʔϯϚον • 3FBTPOͷϕετػೳͷҰͭ
    • ෼ׂ୅ೖʢEFTUSVDUVSJOHʣʹࣅ͍ͯΔ͕ɼܕʹج͍͍ͮͯΔ
    let message = switch (areYouCrushingIt) { | No => “No worries. Keep going!” | Yes => “Great!” | PrettyMuch => “Nice!” }; 10
11. JavaScriptͱͷ૬ޓӡ༻ • ReasonίʔυʹJavaScriptͷίʔυΛຒΊࠐΉ
    Js.log(“this is reason”); [%bs.raw {| console.log(‘here is some javascript for you’) |}]; ҎԼʹίϯύΠϧ͞ΕΔ
    ‘use strict’; console.log(“this is reason”); console.log(‘here is some javascript for you’); • JavaScriptͷ஋ΛReason͔ΒΞΫηε
    let x: string = [%bs.raw {| ‘something’ |}]; ҎԼʹίϯύΠϧ͞ΕΔ
    var x = ( ‘something’ ); 11
12. JavaScriptͱͷ૬ޓӡ༻ʢଓ͖ʣ • طଘͷJavaScriptΛ࢖༻͢Δ
    bs.moduleΛ࢖༻ͯ͠Πϯϙʔτ͢Δ [@bs.module “path”] external dirname : string => string = “dirname”; let root = dirname(“/User/chenglou”); ҎԼʹίϯύΠϧ͞ΕΔ
    var Path = require(“path”); var root = Path.dirname(“/User/chenglou”); 12
13. ίϯύΠϧग़ྗͷྫʢೖྗʣ type schoolPerson = Teacher | Director | Student(string); let greeting = stranger => switch (stranger) { | Teacher => "Hey professor!" | Director => "Hello director." | Student("Richard") => "Still here Ricky?" | Student(anyOtherName) => "Hey, " ++ anyOtherName ++ "." }; Js.log(greeting(Student("Richard"))); 13
14. ίϯύΠϧग़ྗͷྫʢग़ྗʣ // Generated by BUCKLESCRIPT VERSION 3.1.0, PLEASE EDIT WITH CARE 'use strict'; function greeting(stranger) { if (typeof stranger === "number") { if (stranger !== 0) { return "Hello director."; } else { return "Hey professor!"; } } else { var anyOtherName = stranger[0]; if (anyOtherName === "Richard") { return "Still here Ricky?"; } else { return "Hey, " + (anyOtherName + "."); } } } console.log(greeting(/* Student */["Richard"])); exports.greeting = greeting; /* Not a pure module */ 14